1. Field of the Invention
The present invention related to a CRT assembly, and more particularly, to a socket connected to lead pins mounted on a neck portion of the CRT and a socket board, for applying a voltages to the respective lead pins, and a CRT assembly employing the socket.
2. Description of the Related Art
A conventional CRT assembly, as shown in FIGS. 1 and 2, includes a CRT 10, a socket 20 having a plurality of connector pins 22 connected to lead pins 12 on a neck portion 11 of the CRT 10, for applying a voltages to the lead pins 12, and a socket board 30 on which signal lines 31 for applying a voltages to the connector pins 22 are formed in a pattern.
The CRT 10 includes a panel 112 having a fluorescent layer 111, and a funnel 113 sealed to the panel 112. An electron gun 13 is installed in a neck portion 11 of the funnel 113. The electron gun 13 includes a multitude of electrodes 13a fixed to a bead glass 13b at intervals. The respective electrodes 13a of the electron gun 13 are electrically connected to the lead pins 12 by connectors 13c. A plurality of holes 21a in a main body 21 of the socket 20 have the same array pattern as the lead pins 12, and a fixation portion 21b for fixing the connector pins 22 is located at the outer peripheral surface of the main body 21.
A connector pin 22 includes a lead pin holder portion 22a and is inserted into a hold 21a of the main body 21 for to the lead pin 12, and an outer pin portion 22b extending from the lead pin holder portion 22a and fixed to the fixation portion 21b. Here the array center of the lead pin holder portion 22a coincides with that of the outer pin portion 22b. Also, the array angle A between the holes 21a with respect to the array center, that is, the array angle of the lead pin holder portion 22a is the same as the array angle B between the signal lines 31, that is, the array angle of the outer portion 22b.
The signal lines 31 on the socket board 30 correspond to the array pattern of the outer pin portion 22b. A connection hole 31a into which the output pin portion 22b is inserted and soldered is formed in the signal line 31.
Also, the lead pin 12 includes a high-voltage lead pin 12a to which a high voltages are applied and low-voltage lead pins 12b to which low voltage is applied.
In the CRT assembly constructed as above, if the number of the high-voltage lead pins 12a for applying a voltage to focusing electrodes of a main lens of an electron gun, increases due to an increase in the number of the focusing electrodes, the number of the holes 21a of the socket 20 connected thereto must increase as well. Thus, since the array angle A between the holes 21a to which the low-voltage lead pins 12b are connected is reduced a rearrangement is required such that the array angle A between the low-voltage lead pins 12b and the array angle B between the signal lines 31 of the socket board 30 are reduced. Thus, if the number of lead pins changes, even though circuit characteristics for applying a voltage to the electron gun are retained without change, the signal lines 31 of the socket board 30 must be rearranged to satisfy the reduced array angle requirements.
To overcome this problem, as shown in FIG. 2, while the number of lead pins 12 is kept constant, a resistor 14 is installed between an electrode connected to the lead pin 12 and an additionally installed electrode to apply a reduced voltage to the additionally installed electrode.
Since the voltage-reducing resistor 14 is installed within the CRT, it is difficult to install during assembly of the CRT. Also, it is not easy to attain reliability in the course of manufacturing the CRT in which a high-temperature and high-voltage splash process must be carried out. Particularly, when the resistance level is changed due to deteriorated resistance during the manufacturing process, focusing characteristics may be degraded.